Does Pokemon Glazed have mega evolutions?

Yes, Pokemon Glazed does have a mega evolution, although it is not very common. In fact the only Pokemon I've ever seen going through mega-evolution is Riolu.

And how does a Pokemon master get Riolu to mega evolve? The only way is "happiness" apparently.
It takes time, and it's a boring path... I completed Pokemon Emerald in almost the same time it took Riolu to evolve! But in the end it's actually worth the wait because it is awesome.